Objective To explore the clinical manifestations and ultrasound features of primary high-grade serous carcinoma of the fallopian tube (PHGSC-FT) under the new pathological criteria.

Methods A retrospective study was conducted on 45 PHGSC-FT patients diagnosed by postoperative pathology at Obstetrics & Gynecology Hospital of Fudan University from April to June 2023. Clinical data, ultrasound characteristics, and prognosis were analyzed.

Results The age of patients was (56.2±10.1) years, with postmenopausal women accounting for 68.9%. The main clinical symptoms were abdominal pain and (or) distension (53.3%), pelvic mass (31.1%), and abnormal vaginal discharge (11.1%). Preoperative ultrasound revealed that 40 cases presented mainly as solid pelvic or abdominal masses (82.5%, 33/40), while 5 cases involved widely disseminated small lesions not describable by ultrasound; 28 lesions had irregular shapes 70.0%. Intraoperative findings showed that the major lesions were located in the ovary in 27 cases (60.0%), fallopian tube in 7 cases (15.6%), extra-adnexal pelvic in 6 cases (13.3%), and widespread disseminated lesions in 5 cases (11.1%). The accuracy rate of ultrasound localization was 82.2%, and the accuracy rate for benign and malignant differential diagnosis was 75.6%. Serum carbohydrate antigen 125 (CA125) levels were significantly lower in patients whose primary lesion was located in the fallopian tube than in those with lesions outside the fallopian tube (P＝0.001). FIGO stage Ⅰ: 4 cases (8.9%), stage Ⅱ: 10 cases (22.2%), stage Ⅲ: 23 cases (51.1%), and stage Ⅳ: 8 cases (17.8%), with 3-year survival rates of 75.0%, 80.0%, 56.5%, and 50.0%, respectively.

Conclusions PHGSC-FT predominantly occurs in postmenopausal women, and its biological behavior is characterized by “small primary lesion–large metastatic lesion”. Prognosis of these patients is related to FIGO stage; Ultrasound demonstrates high accuracy in localization of large lesions and in determining benign versus malignant nature.